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RC Time Constant

Find the charging time constant for a resistor-capacitor circuit.

Safety first, always.

ElectroLab AI teaches theory, low-voltage electronics, and planning concepts. Mains voltage, switchboards, fixed wiring, high-current systems, and legal electrical work must only be performed by licensed electricians where required.

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Visual schematic

RC charge timer

The resistor controls how quickly the capacitor voltage rises. Bigger R or C means a slower timing action.

Low-voltage model
BatteryResistorCapacitorcapacitor voltage risescharging

TP1: supply

TP2: capacitor voltage

TP3: trigger/output

Diagrams are simplified learning models for low-voltage electronics. They are not wiring instructions for mains, switchboards, fixed wiring, or legal electrical work.

Formula notes

tau = R x C

About five time constants gets a capacitor close to fully charged or discharged.

Visual formula bench

RC timing view

One time constant is the first big move; about five time constants is nearly settled.

Live result

0.00 ms

tau = 0.00 ms5 tau = 0.00 ms

1. Estimate

Load the example or enter a real low-voltage learning value.

2. Visualise

Use the diagram to connect the formula to current path, timing, frequency, or energy flow.

3. Verify safely

Build only suitable low-voltage circuits and confirm with a meter before scaling up.